package com.wc.alorithm_luogu._动态规划.P1044;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.StreamTokenizer;

/**
 * @Author congge
 * @Date 2023/7/19 14:56
 * @description
 */
public class Main {
    public static void main(String[] args) {
        Input sc = new Input();
        int n = sc.nextInt();
        int[][] arr = new int[n + 1][n + 1];
        for (int i = 0; i <= n; i++) {
            arr[0][i] = 1;
        }
        for (int i = 1; i <= n; i++) {
            for (int j = i; j <= n; j++) {
                arr[i][j] = arr[i - 1][j];
                if (i != j) {
                    arr[i][j] += arr[i][j - 1];
                }
            }
        }
        System.out.println(arr[n][n]);
    }
}

class Input {
    StreamTokenizer in = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));

    public int nextInt() {
        try {
            in.nextToken();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return (int) in.nval;
    }
}
